Anti-Inflammatory and Antioxidative Properties of Isoflavones Provide Renal Protective Effects Distinct from Those of Dietary Soy Proteins against Diabetic Nephropathy.

SCOPE: Dietary soy reportedly protects from diabetic nephropathy (DN), but its active components and mechanism of action remain unknown. METHODS AND RESULTS: In this study, KKAy mice are fed three types of diet: Dietary soy isoflavones with soy protein (Soy-IP) diet, reduced isoflavones soy protein (RisoP), and oral administration of isoflavones aglycones (IsoAgc). Albuminuria and glycosuria are decreased only in the soy-IP group. The risoP group show reduced expansion of mesangial matrix and renal fibrosis, the IsoAgc group show renal anti-fibrotic and anti-inflammatory effects; however, these renal pathological changes are repressed in the soy-IP group, suggesting the distinct protective roles of soy protein or isoflavones in DN. The isoflavone genistein has a better inhibitory effect on the inflammatory response and cellular interactions in both mouse tubular cells and macrophages when exposed to high glucose and albumin (HGA). Genistein also represses HGA-induced activator protein 1 activation and reactive oxidases stress generation, accompanied by reduced NADPH oxidase (NOX) gene expression. Finally, diabetic mice show a decrease in lipid peroxidation levels in both plasma and urine, along with lower NOXs gene expression. CONCLUSION: The data elucidate the detailed mechanism by which isoflavones inhibit renal inflammation and provide a potential practical adjunct therapy to restrict DN progression.

The dietary isoflavone daidzein mitigates oxidative stress, apoptosis, and inflammation in CDDP-induced kidney injury in rats: Impact of the MAPK signaling pathway.

Cisplatin-induced nephrotoxicity persists as a clinical problem despite several supportive measures to alleviate renal damage. Daidzein (DZ), a dietary isoflavone having antioxidant and anti-inflammatory activity, is investigated in this study for protective effects against cisplatin-induced renal injury in rats. DZ (25, 50, or 100 mg/kg; intraperitoneally; 10 days) was administered along with Cisplatin, single dose, on the 7th day of the experiment. On the 11th day, the rats were euthanized, and different samples were collected for analysis. Biochemical, histopathological, and molecular parameters were assessed to evaluate the effect of daidzein. Cisplatin injection resulted in renal dysfunction, lipid peroxidation that led to consumption of antioxidants, exaggerated apoptosis, and inflammation. These changes were associated with increase in the signaling proteins. DZ attenuated the toxic effects of cisplatin on the kidney at 100 mg/kg dose. The study concludes with the finding that daidzein imparts protection against the nephrotoxic effect of Cisplatin and can be considered as a novel, potential therapy.

Fish Oil Supplementation Reduces Inflammation but Does Not Restore Renal Function and Klotho Expression in an Adenine-Induced CKD Model.

BACKGROUND: Chronic kidney disease and inflammation promote loss of Klotho expression. Given the well-established anti-inflammatory effects of omega-3 fatty acids, we aimed to investigate the effect of fish oil supplementation in a model of CKD. METHODS: Male C57BL/6 mice received supplementation with an adenine-enriched diet (AD, n = 5) or standard diet (CTL, n = 5) for 10 days. Two other experimental groups were kept under the adenine diet for 10 days. Following adenine withdrawal on the 11th day, the animals returned to a standard diet supplemented with fish oil (Post AD-Fish oil, n = 9) or not (Post AD-CTL, n = 9) for an additional period of 7 days. RESULTS: Adenine mice exhibited significantly higher mean serum urea, creatinine, and renal expression of the pro-inflammatory markers Interleukin-6 (IL-6), C-X-C motif chemokine 10 (CXCL10), and Interleukin-1ß (IL-1ß), in addition to prominent renal fibrosis and reduced renal Klotho gene expression compared to the control. Post AD-Fish oil animals demonstrated a significant reduction of IL-6, C-X-C motif chemokine 9 (CXCL9), and IL-1ß compared to Post AD-CTL animals. However, serum creatinine, renal fibrosis, and Klotho were not significantly different in the fish oil-treated group. Furthermore, renal histomorphological changes such as tubular dilatation and interstitial infiltration persisted despite treatment. CONCLUSIONS: Fish oil supplementation reduced renal pro-inflammatory markers but was not able to restore renal function nor Klotho expression in an adenine-induced CKD model.

Dietary low-fat soy milk powder retards diabetic nephropathy progression via inhibition of renal fibrosis and renal inflammation.

SCOPE: Diabetic nephropathy (DN) is a major cause of end-stage renal disease. Here, we examined the effect of long-term consumption of a low-fat soy milk powder (LFSMP) on the diabetic kidney structure and function. METHODS AND RESULTS: KKAy mice were fed a casein-, LFSMP-, or high-fat soy mixture powder (HFSMP)-based diet for 4 months. Plasma and urine were subjected to a biochemical assay every 2-4 wk. Renal morphology and protein expression were evaluated by histochemical staining and western blots. Although HFSMP-based diet showed no protective effect on DN. LFSMP-fed mice exhibited lower water intake, urine output, and urinary albumin, and glucose excretion. Furthermore, strong preservation of renal structural proteins and low urinary N-acetyl-beta-d-glucosaminidase activity were observed in LFSMP-fed mice, indicating alleviation of renal injury. LFSMP-fed mice showed a lesser degree of mesangial matrix expansion, of tubulointerstitial fibrosis, and of myofibroblast differentiation. Finally, milder renal inflammation was found in LFSMP-fed mice, as evidenced by a decrease in urinary monocyte chemoattractant protein- 1 excretion and lesser macrophage infiltration into the tubulointerstitium. CONCLUSION: The present data suggests that long-term consumption of LFSMP but not HFSMP retards DN progression via suppressing renal injury, myofibroblast differentiation, and renal macrophage infiltration in diabetic condition.

Role of chemokines in proteinuric kidney disorders.

Experimental and human studies have shown that proteinuria contributes to the progression of renal disease. Overexposure to filtered proteins promotes the expression and release of chemokines by tubular epithelial cells, thus leading to inflammatory cell recruitment and renal impairment. This review focuses on recent progress in cellular and molecular understanding of the role of chemokines in the pathogenesis of proteinuria-induced renal injury, as well as their clinical implications and therapeutic potential.

Effect of dietary soy protein on tumor necrosis factor productivity in macrophages from nephritic and hepatoma-bearing rats.

The present study investigated the effect of dietary soy protein isolate (SPI) on tumor necrosis factor-alpha (TNF) productivity in peritoneal macrophages from nephritic and hepatoma-bearing rats. Dietary SPI significantly inhibited the elevated production of TNF by lipopolysaccharide-stimulated macrophages in nephritic and hepatoma-bearing rats compared with dietary casein, while it exerted no influence on the TNF productivity in normal rats. Removal of the minor components contained in SPI by ethanol extraction could significantly or partially restore the reduced TNF production caused by SPI in nephritic and hepatoma-bearing rats, respectively. These results suggest that dietary SPI could suppress the enhanced productivity of TNF associated with the progression of nephritis and hepatoma, and some factors existing in the ethanol extract of SPI are suggested to be involved in suppressing TNF productivity by macrophages.

Importance of early and continuous use of protein restriction on the progression of adriamycin nephropathy.

Three experimental protocols were carried out with the aim of evaluating the role of protein restriction on the progression of the established adriamycin-induced nephropathy, and whether the protective effect of the diet persists after the diet is discontinued. The effect of a low protein diet (LPD) was studied for 6 weeks in protocol 1, 16 weeks in protocol 2 and for 28 weeks in protocol 3. In protocol 3, one group (LL) received LPD and another (NN) was given a normal protein diet (NPD). A third group (LN) received LPD for 16 weeks and then NPD for 12 weeks and a fourth group (NL) was fed NPD for 16 weeks and then LPD for 12 weeks. In protocol 1 the tubulo-interstitial index (TILI) of rats on LPD (Md = 2, P25 = 0.0; P75 = 3.5) after six weeks, was smaller than that of the animals on NPD (Md = 6.0; P25 = 3.0; P75 = 8.0; p < 0.05). In protocol 2, the group taking LPD presented an area of interstitial fibrosis (IF) (Md = 0.5%, P25 0.2%; P75 = 1.9%) smaller than that of the NPD group (Md = 6.8%; P25 = 5.2%; P75 = 7.1%; p < 0.05). No significant difference in the area of glomerulosclerosis (GSA) was observed between the animals on LPD (Md = 0.0%; P25 = 0.0%, P75 = 0.0%) and NPD (Md = 0.37%; P25 = 02%, P75 = 1.25%; p > 0.05). In protocol 3, the group LL showed GSA (Md = 1.3%; P25 0.6%, P75 = 2.5%) and IF (Md = 3.6%; P25 = 1.6%; P75 = 5.9%) smaller that those of LN (GSA Md = 10.1%; P25 = 6.6%; P75 = 14.8%; IF: Md = 17.3%; P25 = 14.1%; P75 = 24.5%), NL (GSA: Md = 9.1%; P25 = 5.8%; P75 = 11.7%; IF: Md = 25.0%; P25 = 20.4%; P75 = 30%), and NN (GSA: Md = 6.75%; P25 = 4.9%; P75 = 11.7%; IF: Md = 20.9%; P25 = 16.2%; P75 = 32.4%). In conclusion, in order to be effective, LPD must be introduced early and maintained for a long period of tune.

Reduction of hyperlipidemia and proteinuria without growth retardation in nephritic rats by a methionine-supplemented, low-soy-protein diet.

Effect of a low-soy-protein-isolate (SPI) diet supplemented with methionine on hyperlipidemia, proteinuria, and hypoalbuminemia was studied in rats with nephrotoxic serum nephritis (NSN). Rats were fed experimental diets for 14 d after an injection of nephrotoxic serum. An 8.5%-SPI diet (8.5S), as compared with a basal 20%-SPI diet (20S), improved the hyperlipidemia, proteinura, and hypoalbuminemia secondary to NSN but retarded the growth of rats. The addition of 0.3% methionine to 8.5S (8.5SM) alleviated the growth retardation without loss of the above-mentioned beneficial effects. 8.5SM was found to suppress hepatic cholesterol synthesis compared with 20S. These results suggest that the methionine-supplemented low-SPI diet has a beneficial effect on hyperlipidemia, proteinuria, and hypoalbuminemia without inducing either growth retardation or severe fatty liver in nephritis. They also suggest that the hypocholesterolemic effect of 8.5SM in nephritic rats may be partly attributable to reduced hepatic cholesterol synthesis.

[New approaches to the treatment of nephritis]. / Novye podkhody k lecheniiu nefritov.

The paper provides evidence and results of using new therapeutical treatment of glomerulonephritis, such as pulse-therapy with cyclophosphane, therapy with angiotension-converting enzyme (ACE) inhibitors or that with antihyperlipidemic agents. Based on much experience with pulse-therapy with cyclophosphane (over 100 patients with chronic glomerulonephritis (CGN) and lupus nephritis), it is concluded that this method is highly effective. Treating 57 patients with ACE inhibitors has shown that in CGN these drugs should be used only when taking into account their antihypertensive effect and capacity of lowering intraglomerular hypertension, as evidenced by the renal functional reserve, and diminishing proteinuria. The long-term (7-12 month) antihyperlipidemic therapy (diet and lovastatin) in 20 patients with CGN accompanied by the nephrotic syndrome caused a significant reduction in the concentration of serum cholesterol and proteinuria, a significant increase in serum albumin levels; remission of the nephrotic syndrome occurred in 9 patients; but better effects were observed in non-inflammatory nephropathies, such as membranous nephropathy, focal segmental glomerulosclerosis, and nephrosclerosis.

[Means for the inhibition of the nonimmune progression of nephritis]. / Puti tormozheniia neimmunnogo progressirovaniia nefritov.

Inhibition of non-immune progression of renal insufficiency for control of glomerulonephritis was attempted via hemodynamic, metabolic and hypolipidemic means. Hemodynamic correction was conducted using inhibitors of angiotensin-converting enzyme capoten and renitek. The action on metabolic factors of progression was realized by lovastatin mevakor. Capoten and renitek exhibited in 57 patients with chronic nephritis not only a hypotensive effect, but also reduced intraglomerular hypertension and proteinuria. A long-term (7-12 months) hypolipidemic therapy (diet and lovastatin) in 20 patients with chronic glomerulonephritis with nephrotic syndrome resulted in lowering of serum cholesterol concentrations and proteinuria, raised serum albumin. 9 patients achieved remission of nephrotic syndrome. The highest effect occurred in non-inflammatory nephropathy: membranous nephropathy, focal-segmental glomerulosclerosis, nephrosclerosis.

A fish oil diet preserves renal function in nephrotoxic serum nephritis.

Fish oil diets preserve renal function in murine lupus, but we have found that these diets accelerate renal deterioration in renoprival nephropathy. In this study we examined the effects of dietary fish oil in accelerated nephrotoxic serum nephritis. For 1 month, 14 female rats were fed diets that differed only in fat composition, containing either menhaden (fish) oil or beef tallow (control). Rats were then preimmunized with rabbit IgG and, 5 days later, were injected with nephrotoxic serum. Glomerular filtration rate (GFR) was measured continuously in conscious animals by means of intraperitoneal 14C-labeled inulin minipumps. Fish oil-containing diets markedly attenuated the nephrotoxic serum-induced decline in GFR and the rise in proteinuria and significantly reduced glomerular prostaglandin E2 and thromboxane A2. The results of tests of renal histology showed no differences between the two groups. Five days after preimmunization, rats fed fish oil had more rabbit IgG remaining in their serum and had mounted less of an antibody response to the rabbit IgG. Fish oil diets also resulted in an attenuated disappearance of injected 14C-labeled rabbit IgG. In vitro, peritoneal macrophages from rats fed fish oil took up less rabbit IgG than macrophages from rats fed control diets. Thus the beneficial effects of a fish oil diet may result from defective immune surveillance and from alterations in eicosanoids.

[Effect of diet therapy on iron metabolism in chronic kidney disease]. / Vliianie dieticheskoi terapii na obmen zheleza u bol'nykh s khronicheskim zabolevaniem pochek.

A modified Giordano-Giovanetti diet has a beneficial therapeutic effect in the treatment of azotemia and uremia. The diet is capable of maintaining nitrogenous equilibrium for a long period of time. However, the chemical composition of the diet does not meet iron requirements of patients with chronic renal diseases. Besides, the quantitative ratio of the ingredients such as proteins and carbohydrates has an adverse effect on iron absorption, the greatest portion of iron contained by the diet is bound with products of plant origin and absorbed by the body to a negligible degree. It is recommended that the diet suggested be supplemented with readily available iron preparations.

A diet enriched with eicosapentaenoic acid suppresses autoimmune nephritis in female (NZB x NZW) F1 mice.

A diet containing menhaden oil, rich in EPA, protected (NZB x NZW) F1 mice from developing lupus nephritis. Only 16% of mice treated with this diet from 5-6 weeks of age developed severe renal disease by 19 months of age, as opposed to 100% of controls. The menhaden oil diet, when delayed until mice were 5 months of age, also reduced the incidence of renal disease, and under these conditions anti-n-DNA and anti-ss-DNA antibodies were similar in treated and control groups. We suggest that EPA, an AA analogue, may reduce inflammation by altering the production of PGs and LTs.